1. Field of the Invention
The present invention relates to a color identifying apparatus and a color identifying method, and more particularly to a color identifying apparatus and a color identifying method for specifying a gas by identifying the color of a reaction surface which is produced by a color reaction with the gas.
2. Description of the Related Art
There have heretofore been known gas detecting devices for causing a chemical reaction between a gas such as a toxic gas and chemical reagents to change the colors of the chemical reagents. For example, U.S. Pat. No. 6,228,657B1 discloses an M256 chemical agent detection kit.
The gas detecting device includes a plurality of ampules containing respective chemical reagents of different types and a plurality of reaction surfaces such as paper surfaces. When the ampules are crushed, the chemical reagents contained therein flow into the reaction surfaces.
The chemical reagents as they flow into the reaction surfaces chemically react with a gas that is held in contact with the reaction surfaces. The chemical reaction causes the chemical reagents to change their colors, and the reaction surfaces also change their colors depending on the color changes of the chemical reagents.
The user of the gas detecting device introduces different chemical reagents into the respective reaction surfaces, and recognizes the concentration of the gas based on the color changes of the reaction surfaces.
U.S. Pat. No. 6,228,657B1 also reveals a reader device for outputting a signal depending on the color of a reaction surface using three photodiodes or a single color CCD sensitive to the colors of R, G, B (red, green, and blue).
The brightness of the color of a reaction surface, which is caused by a color reaction with a gas, varies depending on the concentration of the gas. Therefore, the brightness of the reaction surface varies if the concentration of the gas varies even though the components of the gas remain the same.
Consequently, if the color of an actual reaction surface is specified by checking the data of the color read from the actual reaction surface against the pre-registered data of the colors of reaction surfaces, then since it is necessary to pre-register the data of colors produced by color reactions with a gas at different concentrations, the amount of data required to be pre-registered is very large.